Oleic Acid Modified Fe3O4 Nanoparticles Research Articles

A magnetic “Band-Aid” incorporated with Fe3O4 NPs modified epoxy binder for in-situ repair of organic coating under seawater

To repair the anti-corrosive coatings directly under seawater is an up-and-coming approach, which can effectively prolong the service life of coated steel structures once the coatings suffered from unexpected scratches. Inspired by the design of Band-Aid for the healing of wound, a magnetic “Band-Aid” (MB) combined with oleic acid modified Fe3O4 nanoparticles (OMNPs) was designed to realize the in-situ repair of anti-corrosion coatings under seawater and the experimental results indicated that this coating repair method by MB incorporated with OMNPs modified epoxy binder is satisfying and effective when the addition of OMNPs epoxy binder was more than 1.0 wt%. Furthermore, the penetration of seawater in the vertical direction of the coating can be prevented by MB during the curing process of epoxy binder, the formation of permeation channels parallel to the coating can be blocked with the aid of OMNPs, which mainly based on the magnetic force between the MB and substrate steel, as well as the competitive-wetting and target-driving functions of OMNPs. The current work may provide a feasible approach to repair the organic anti-corrosion coating directly, which coated on the steel structures under seawater.

PH-Responsible Doxorubicin-Loaded Fe3O4@CaCO3 Nanocomposites for Cancer Treatment

A magnetic nanocomposite (MNC) is an integrated nanoplatform that combines a set of functions of two types of materials. A successful combination can give rise to a completely new material with unique physical, chemical, and biological properties. The magnetic core of MNC provides the possibility of magnetic resonance or magnetic particle imaging, magnetic field-influenced targeted delivery, hyperthermia, and other outstanding applications. Recently, MNC gained attention for external magnetic field-guided specific delivery to cancer tissue. Further, drug loading enhancement, construction stability, and biocompatibility improvement may lead to high progress in the area. Herein, the novel method for nanoscale Fe3O4@CaCO3 composites synthesis was proposed. For the procedure, oleic acid-modified Fe3O4 nanoparticles were coated with porous CaCO3 using an ion coprecipitation technique. PEG-2000, Tween 20, and DMEM cell media was successfully used as a stabilization agent and template for Fe3O4@CaCO3 synthesis. Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) data were used for the Fe3O4@CaCO3 MNC's characterization. To improve the nanocomposite properties, the concentration of the magnetic core was varied, yielding optimal size, polydispersity, and aggregation ability. The resulting Fe3O4@CaCO3 had a size of 135 nm with narrow size distributions, which is suitable for biomedical applications. The stability experiment in various pH, cell media, and fetal bovine serum was also evaluated. The material showed low cytotoxicity and high biocompatibility. An excellent anticancer drug doxorubicin (DOX) loading of up to 1900 µg/mg (DOX/MNC) was demonstrated. The Fe3O4@CaCO3/DOX displayed high stability at neutral pH and efficient acid-responsive drug release. The series of DOX-loaded Fe3O4@CaCO3 MNCs indicated effective inhibition of Hela and MCF-7 cell lines, and the IC 50 values were calculated. Moreover, 1.5 μg of the DOX-loaded Fe3O4@CaCO3 nanocomposite is sufficient to inhibit 50% of Hela cells, which shows a high prospect for cancer treatment. The stability experiments for DOX-loaded Fe3O4@CaCO3 in human serum albumin solution indicated the drug release due to the formation of a protein corona. The presented experiment showed the "pitfalls" of DOX-loaded nanocomposites and provided step-by-step guidance on efficient, smart, anticancer nanoconstruction fabrication. Thus, the Fe3O4@CaCO3 nanoplatform exhibits good performance in the cancer treatment area.

NIR light-steered magnetic liquid marbles with switchable positive/negative phototaxis

This work has demonstrated a magnetic liquid marble of switchable positive/negative phototaxis and excellent mechanical stability by encapsulating water droplet with oleic acid modified Fe3O4 nanoparticles (Fe3O4@OA NPs). The as-constructed marble can reach a height up to 4.7 mm, indicating an effective surface tension of ∼54 mN m−1. The marble on water surface can be steered by NIR light as well as magnetic field due to the photothermal effect and superparamagnetic feature of the Fe3O4@OA NPs. Its light-steered motion stems from the photothermal effect-induced Marangoni flow with speed controlled by the incident angles and light intensities. More interestingly, the marble can alter the motion direction from toward (positive phototaxis) to away from (negative phototaxis) NIR light source by simply changing the light irradiation position from upper to lower semi-marbles due to the unique light absorbance/transmittance characteristics of the Fe3O4@OA NPs. This is dramatically different from previously reported light-driven active matters that only show single phototaxis. This finding provides an advanced strategy to remotely steer magnetic liquid marbles, which may stimulate the exploitation of their application in chemistry and biology fields at microscale, and enlightens a method for phototactic regulation of active matters.

Morphological insights into the catalytic aquathermolysis of crude oil with an easily prepared high-efficiency Fe3O4-containing catalyst

Elucidating the underlying structure-performance relationship of Fe3O4-containing catalysts for the aquathermolysis of crude oil is essential for the design of efficient heterogeneous catalysts. Therefore, recyclable Fe3O4 nanoparticles (NPs) with different morphology and particle size were first prepared and tested for catalytic aquathermolysis. The easily prepared Fe3O4 NPs with irregular morphology (L-Fe3O4) have larger intercrystalline mesopores than oleic acid-modified Fe3O4 NPs. This leads to enhanced mass transfer ability, more accessible active sites and thus better aquathermolysis performance. Moreover, these L-Fe3O4 NPs were loaded on a heulandite support by a scalable co-precipitation method, and this L-Fe3O4/heulandite catalyst showed very good performance in catalytic aquathermolysis, with a viscosity decrease of extra-heavy crude oil of 85.0%. The underlying structure-performance relationship was systematically investigated by XRD, HRTEM, EDX-mapping, FT-IR, elemental analysis, SARA (saturate, aromatic, resin and asphaltene) analysis and 1H NMR. The Fe3O4/heulandite catalyst broke C–S bonds and reduced the resin and asphaltene content of the oil. This work is important for the design of Fe3O4-containing catalysts in catalytic aquathermolysis.

Surfactant‐enhanced spectrofluorimetric detection after magnetic nanoparticles‐based micro‐solid‐phase extraction coupled with dispersive liquid–liquid micro‐extraction for determination of ciprofloxacin in human plasma

A sensitive and fast micro-solid-phase extraction (μ-SPE) coupled with dispersive liquid–liquid micro-extraction (DLLME) was reported before micelle enhanced spectrofluorimetric detection for determination of ciprofloxacin antibiotic in human plasma samples. The DLLME was performed using methanol as disperser and 1-octanol as extracting solvent. Oleic acid-modified Fe3O4 nanoparticles (as hydrophobic adsorbents) were applied in μ-SPE step to extract the analyte from DLLME procedure. The method uses the advantageous of high surface area and strong superparamagnetism of these nanoparticles to many avoid labourhood column/cartridge-passing processes of traditional SPE. The major parameters affecting signal enhancement and analyte recovery were evaluated and optimised. Under the optimal conditions, the calibration curve (with calibration equation of I f = 2.5826 C + 10.273) was linear in the range 0.5–600 μg L−1 (R 2 = 0.997) with low limit of detection of 0.21 µg L−1 and limit of quantification of 0.63 µg L−1. The intra-day and inter-day precisions (as relative standard deviation) were in the range of 1.01–1.67% and high recoveries in the range of 93.5–102.4% were obtained. The results demonstrated that the proposed method is easy, low cost, and accurate. In addition, it confirms that choosing extraction solvent was not restricted to the high-density solvents which can extent the versatility of DLLME.

Insight into the influence of OA-Fe3O4 nanoparticles on the morphology and scCO2 batch-foaming behavior of cocontinuous LLDPE/PS immiscible blends at semi-solid state

The influence of oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles on the morphology and foaming behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of phase structure from cocontinuous structure to sea-island structure, when enough amounts of nanoparticles were added. Meanwhile the introduction of enough amounts of OA-Fe3O4 nanoparticles effectively enhanced the foaming ability of LLDPE/PS blend at semi-solid state during scCO2 batch foaming. The mechanism analysis for the change of foaming behavior showed that the improved foaming capacity resulted from the change of the phase structure of LLDPE/PS blends and heterogeneous nucleation of OA-Fe3O4 nanofillers. Sorption and desorption measurements showed that the addition of OA-Fe3O4 nanoparticles in the LLDPE/PS blend increased the solubility of CO2, and the presence of enough amount of OA-Fe3O4 decreased the desorption rate of CO2 in the initial period of depressurization process, which are beneficial to cell nucleation and growth. Furthermore, it was found that the melt behavior and crystalline properties of LLDPE/PS blends were not the key factors to improved foaming behavior of the blends in the presence of OA-Fe3O4 nanoparticles.

Magnetic Solid-Phase Extraction Combined with Dispersive Liquid-Liquid Microextraction Followed by HPLC for Determination of Four Aromatic Amines Released from Azo Dyes in Paper Samples

A novel extraction technique combining dispersive liquid-liquid microextraction (DLLME) with magnetic solid-phase extraction (MSPE) is presented for pre-concentration of four primary aromatic amines (PAAs) released from azo dyes in paper samples prior to high performance liquid chromatography (HPLC). n-Octanol was used as the extractant and hydrophobic oleic acid modified Fe3O4 nanoparticles (Fe3O4@OA NPs) as an efficient adsorbent was applied to retrieve the PAAs-containing n-octanol in the DLLME step. Because of the rapid mass transfer associated with the DLLME and MSPE steps, fast extraction could be achieved. The main parameters affecting the efficiency of MSPE-DLLME procedure of PAAs were investigated and optimized. Under optimum conditions, the recoveries ranged from 79.6 to 88.5% and the limits of detection (LODs) were in the range of 0.21-1.16 ng mL-1 (S / N = 3). The intra-day precision (relative standard deviation (RSD)) was below 7.8% and inter-day RSD was less than 11%.

Magnetic Solid-Phase Extraction in Combination with Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry Analysis: Quantification of Risperidone and 9-Hydroxyrisperidone in Biological Samples

Oleic acid modified Fe3O4 nanoparticles were proposed for magnetic solid-phase extraction coupled with ultra high-performance liquid chromatography-tandem mass spectrometry to determine risperidone (RISP) and 9-hydroxyrisperidone (9OHR) in biological samples. The effects of various experimental parameters including adsorbent amount, pH, adsorption time, eluent type and concentration were systematically investigated. Under optimal conditions, the calibration curve was linear within the concentration range of 0.2-200 ng mL-1 with the correlation coefficient (r) of 0.9962 and the lower limit of quantification was 0.06 ng mL-1 for RISP; the calibration curve was linear within the concentration range of 0.2-200 ng mL-1 with the correlation coefficient of 0.9956 and the lower limit of quantification was 0.04 ng mL-1 for 9OHR. The extraction recoveries were over 90.0% with relative standard deviation less than 5.0%. All these results suggested that magnetic extraction method can be used for enrichment and quantification of RISP and 9OHR in biological samples.

Fabrication of redox and pH dual-responsive magnetic graphene oxide microcapsules via sonochemical method

In this study, the biocompatible redox and pH dual-responsive magnetic graphene oxide microcapsules (MGOMCs) were prepared by a simple sonochemical method. The disulfide bonds cross-linked the wall of MGOMCs were formed from the hydrosulfuryl on the surface of thiolated graphene oxide, which was synthesized by functionalizing graphene oxide with cysteine, showed an excellent redox-responsive property to control drugs release. Moreover, oleic acid modified Fe3O4 nanoparticles were encapsulated into the microcapsules successfully with the hydrophobic drugs dispersed in the hydroxy silicone oil. The MGOMCs possess distinguished magnetic property and pH-responsive ability. Besides, the microcapsules could be engulfed by Hela cells successfully due to the appropriate size and flexible shell. The MGOMCs could be a good carrier for hydrophobic drugs, especially the anticancer drugs.

Preparation of magnetic and pH-responsive chitosan microcapsules via sonochemical method

Magnetic and pH-responsive chitosan microcapsules (MPRCMCs) were prepared by a simple sonochemical method. Superparamagnetic oleic acid modified Fe3O4 nanoparticles (OA-Fe3O4 NPs) and hydrophobic drugs could be directly loaded into MPRCMCs during sonication. The obtained microcapsules had a well-defined spherical morphology with the average size of 2 μm. The microcapsules showed an excellent magnetic property. In addition, the pH-responsive controlled release of coumarin 6 (C6) from MPRCMCs indicated that the developed microcapsules could be a promising candidate for drugs carriers.

Folate-bovine serum albumin functionalized polymeric micelles loaded with superparamagnetic iron oxide nanoparticles for tumor targeting and magnetic resonance imaging

Polymeric micelles functionalized with folate conjugated bovine serum albumin (FA-BSA) and loaded with superparamagnetic iron oxide nanoparticles (SPIONs) are investigated as a specific contrast agent for tumor targeting and magnetic resonance imaging (MRI) in vitro and in vivo. The SPIONs-loaded polymeric micelles are produced by self-assembly of amphiphilic poly(HFMA-co-MOTAC)-g-PEGMA copolymers and oleic acid modified Fe3O4 nanoparticles and functionalized with FA-BSA by electrostatic interaction. The FA-BSA modified magnetic micelles have a hydrodynamic diameter of 196.1nm, saturation magnetization of 5.5emu/g, and transverse relaxivity of 167.0mM−1S−1. In vitro MR imaging, Prussian blue staining, and intracellular iron determination studies demonstrate that the folate-functionalized magnetic micelles have larger cellular uptake against the folate-receptor positive hepatoma cells Bel-7402 than the unmodified magnetic micelles. In vivo MR imaging conducted on nude mice bearing the Bel-7402 xenografts after bolus intravenous administration reveals excellent tumor targeting and MR imaging capabilities, especially at 24h post-injection. These findings suggest the potential of FA-BSA modified magnetic micelles as targeting MRI probe in tumor detection.

Application of dispersive liquid–liquid microextraction coupled with vortex-assisted hydrophobic magnetic nanoparticles based solid-phase extraction for determination of aflatoxin M1 in milk samples by sensitive micelle enhanced spectrofluorimetry

An efficient, simple and fast low-density solvent based dispersive liquid–liquid microextraction (LDS-DLLME) followed by vortex-assisted dispersive solid phase extraction (VA-D-SPE) has been developed as a new approach for extraction and preconcentration of aflatoxin M1 in milk samples prior to its micelle enhanced spectrofluorimetic determination. In this LDS-DLLME coupled VA-D-SPE method, milk samples were first treated with methanol/water (80:20, v/v) after removing the fat layer. This solvent was directly used as the dispersing solvent in DLLME along with using 1-heptanol (as a low-density solvent with respect to water) as the extracting solvent. In VA-D-SPE approach, hydrophobic oleic acid modified Fe3O4 nanoparticles were used to retrieve the analyte from the DLLME step. It is considerably that the target of VA-D-SPE was 1-heptanol rather than the aflatoxin M1 directly. The main parameters affecting the efficiency of LDS-DLLME and VA-D-SPE procedures and signal enhancement of aflatoxin M1 were investigated and optimized. Under the optimum conditions, the method was linear in the range from 0.02 to 200µgL−1 with the correlation coefficient (R2) of 0.9989 and detection limit of 13ngL−1. The intra-day precision was 2.9 and 4.3% and the inter-day precision was 2.1 and 3.3% for concentration of 2 and 50µgL−1 respectively. The developed method was applied for extraction and preconcentration of AFM1 in three commercially available milk samples and the results were compared with the official AOAC method.

Self-assembled magnetic luminescent hybrid micelles containing rare earth Eu for dual-modality MR and optical imaging

In this study, we report new water-soluble multifunctional nanomaterials based on amphiphilic poly(HFMA-co-Eu(AA)3Phen)-g-PEG copolymers and oleic acid modified Fe3O4 nanoparticles. The nanoparticles can self-assemble to form magnetic and luminescent hybrid micelles and show a spherical morphology, paramagnetic properties with a maximum saturation magnetization of 7.05 emu g-1, and a high transverse relaxivity of 340 mM-1 s-1. According to in vivo magnetic resonance imaging (MRI) experiments, excellent contrast of the liver and spleen was achieved after injection of the hybrid micelles. Fluorescence spectra show characteristic emission peaks from the rare earth Eu at 616 nm and vivid red fluorescence can be observed by 2-photon confocal laser scanning microscopy (CLSM). In vivo optical imaging demonstrates the unique fluorescent characteristics of the magnetic and luminescent hybrid micelles in the liver and spleen and the excellent multifunctional properties suggest the possibility of clinical use as nanocarriers in magnetic resonance imaging and optical imaging.

Microemulsion synthesis and electromagnetic wave absorption properties of monodispersed Fe3O4/polyaniline core–shell nanocomposites

Monodispersed Fe3O4/PANI core–shell nanocomposites were synthesized by microemulsion polymerization. Before the polymerization of aniline, Fe3O4 nanoparticles were prepared by thermal decomposition of iron acetylacetonate using benzyl alcohol as the solvent and were surface-modified by oleic acid. Then aniline monomer was polymerized on the surface of Fe3O4 nanoparticles by microemulsion polymerization with sodium dodecyl benzene sulfonate as the surfactant and ammonium persulfate as the oxidant. Fourier transform infrared (FT-IR) spectra indicated that the oleic acid was chemisorbed on the surface of Fe3O4 nanoparticles. Transmission electron microscopy (TEM) analysis showed that the oleic acid modified Fe3O4 nanoparticles had a better dispersity with a diameter around 10nm. The Fe3O4/PANI nanocomposites were monodisperse with Fe3O4 as the magnetic core and PANI as the conductive shell. The as-prepared Fe3O4/PANI nanocomposites showed a superparamagnetic behavior. The paraffin composites with 70wt.% Fe3O4/PANI powders provided good electromagnetic wave absorption performance (RL<−20dB) in the range of 10.01–16.98GHz with absorber thicknesses of 3–4mm. A minimum RL value of −25.40dB was observed at 10.52GHz with a thickness of 3mm.

Multifunctional nanocomposites of lanthanide (Eu3+, Tb3+) complexes functionalized magnetic mesoporous silica nanospheres covalently bonded with polymer modified ZnO

Methacrylic-group-modified ZnO nanoparticles (designated ZnO-MAA) prepared through the sol-gel process are copolymerized with 2-hydroxyethyl methacrylate (HEMA) to form ZnO-MAA-PHEMA hybrid system. ZnO-MAA-PHEMA unit is functionalized with 3-(triethoxysilyl)-propyl isocyanate (TEPIC) to form ZnO-MAA-PHEMA-Si hybrids, and then is incorporated with oleic acid-modified Fe3O4 nanoparticles by co-condensation of tetraethoxysilane (TEOS) and ZnO-MAA-PHEMA-Si. Subsequently, ZnO-polymer covalently bonded mesoporous silica nanospheres are assembled using cetyltrimethylammonium bromide (CTAB) surfactant as template. Furthermore, lanthanide (Eu(3+), Tb(3+)) complexes with nicotinic acid (NTA), isonicotinic acid (INTA) and 2-chloronicotinic (CNTA) are introduced by coordination bonds, resulting in the final multifunctional nanocomposites. The detailed physical characterization of these hybrids is discussed in detail. It reveals that they possess both magnetic and luminescent properties. Especially Eu(ZnO-MMS)(CNTA)3 and Tb(ZnO-MMS)(NTA)3 present high quantum yield values of 32.2% and 68.5%, respectively. The results will lay the foundation for further application in biomedical and biopharmaceutical fields.

Magnetite-loaded fluorine-containing polymeric micelles for magnetic resonance imaging and drug delivery

Magnetite (Fe3O4) – loaded polymer micelles (denoted as “magnetomicelles”) are produced by self-assembly of fluorine-containing amphiphilic poly(HFMA-g-PEGMA) copolymers with oleic acid modified Fe3O4 nanoparticles in an aqueous medium. The oleic acid modified Fe3O4 nanoparticles form small clusters in the poly(HFMA-g-PEGMA) micelles with a mean diameter of 100 nm and the magnetomicelles show high stability in an aqueous medium due to the high hydrophobic fluorine segments in graft copolymers enhance the stability of the micelles. The magnetomicelles also show good cytocompatibility based on the MTT cytotoxicity assay and possess paramagnetic properties with saturation magnetization of 17.14 emu/g.Their good stability, cytocompatibility, and paramagnetic properties render the materials attractive in drug delivery and in vivo magnetic resonance imaging (MRI) applications. Controlled release of hydrophobic drug-5-fluorouracil is achieved from the magnetomicelles with a loading efficiency of 20.94 wt%. The magnetomicelles have transverse relaxivity rates (r2) of 134.27 mM−1 s−1 and exhibit high efficacy as a negative MRI agent in T2-weighted imaging. In vivo MRI studies demonstrate that the contrast between liver and spleen is enhanced by the magnetomicelles. These favorable properties suggest clinical use as nanocarriers in drug delivery applications and contrast agents in MRI.